Bump indexmap from 1.3.2 to 1.4.0

Bumps [indexmap](https://github.com/bluss/indexmap) from 1.3.2 to 1.4.0.
- [Release notes](https://github.com/bluss/indexmap/releases)
- [Commits](https://github.com/bluss/indexmap/compare/1.3.2...1.4.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Cargo.lock

@@ -751,9 +751,9 @@ checksum = "e0bd112d44d9d870a6819eb505d04dd92b5e4d94bb8c304924a0872ae7016fb5"
 
 [[package]]
 name = "indexmap"
-version = "1.3.2"
+version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "076f042c5b7b98f31d205f1249267e12a6518c1481e9dae9764af19b707d2292"
+checksum = "c398b2b113b55809ceb9ee3e753fcbac793f1956663f3c36549c1346015c2afe"
 dependencies = [
  "autocfg",
 ]

zebra-network/Cargo.toml

@@ -15,7 +15,7 @@ chrono = "0.4"
 hex = "0.4"
 # indexmap has rayon support for parallel iteration,
 # which we don't use, so disable it to drop the dependencies.
-indexmap = { version = "1.3", default-features = false }
+indexmap = { version = "1.4", default-features = false }
 pin-project = "0.4"
 proptest = "0.10"
 proptest-derive = "0.2.0"